[PATCH v6 4/5] zram: validate parameters in each backend's setup_params

[Haoqin Huang]

From: Haoqin Huang <haoqinhuang@xxxxxxxxxxx>

Dict and level parameters are silently accepted even for backends
that do not support them. Validate these parameters in each backend's
.setup_params() to reject unsupported combinations and out-of-range
levels with a specific error message.

Signed-off-by: Haoqin Huang <haoqinhuang@xxxxxxxxxxx>
Signed-off-by: Rongwei Wang <zigiwang@xxxxxxxxxxx>
---
 drivers/block/zram/backend_842.c     |  8 ++++++++
 drivers/block/zram/backend_deflate.c | 13 ++++++++++++-
 drivers/block/zram/backend_lz4.c     |  6 +++++-
 drivers/block/zram/backend_lz4hc.c   | 12 +++++++++++-
 drivers/block/zram/backend_lzo.c     |  8 ++++++++
 drivers/block/zram/backend_lzorle.c  |  8 ++++++++
 drivers/block/zram/backend_zstd.c    |  7 ++++++-
 7 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/drivers/block/zram/backend_842.c b/drivers/block/zram/backend_842.c
index d9b8a6bba2cb..3846a04c69d7 100644
--- a/drivers/block/zram/backend_842.c
+++ b/drivers/block/zram/backend_842.c
@@ -15,6 +15,14 @@ static void release_params_842(struct zcomp_params *params)
 
 static int setup_params_842(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
diff --git a/drivers/block/zram/backend_deflate.c b/drivers/block/zram/backend_deflate.c
index ee26e6c9282f..f71b11bcac78 100644
--- a/drivers/block/zram/backend_deflate.c
+++ b/drivers/block/zram/backend_deflate.c
@@ -24,8 +24,19 @@ static void deflate_release_params(struct zcomp_params *params)
 
 static int deflate_setup_params(struct zcomp_params *params)
 {
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = Z_DEFAULT_COMPRESSION;
+	} else if (params->level < Z_DEFAULT_COMPRESSION ||
+		   params->level > Z_BEST_COMPRESSION) {
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
+
 	if (params->deflate.winbits == ZCOMP_PARAM_NOT_SET) {
 		params->deflate.winbits = DEFLATE_DEF_WINBITS;
 	} else {
diff --git a/drivers/block/zram/backend_lz4.c b/drivers/block/zram/backend_lz4.c
index 6d58956ed5b2..1e28104ad964 100644
--- a/drivers/block/zram/backend_lz4.c
+++ b/drivers/block/zram/backend_lz4.c
@@ -32,8 +32,12 @@ static int lz4_setup_params(struct zcomp_params *params)
 	LZ4_stream_t *dict_stream;
 	int ret;
 
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = LZ4_ACCELERATION_DEFAULT;
+	} else if (params->level < LZ4_ACCELERATION_DEFAULT) {
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
 
 	if (!params->dict || !params->dict_sz)
 		return 0;
diff --git a/drivers/block/zram/backend_lz4hc.c b/drivers/block/zram/backend_lz4hc.c
index c0c3715087c8..d8aa01bb258f 100644
--- a/drivers/block/zram/backend_lz4hc.c
+++ b/drivers/block/zram/backend_lz4hc.c
@@ -22,8 +22,18 @@ static void lz4hc_release_params(struct zcomp_params *params)
 
 static int lz4hc_setup_params(struct zcomp_params *params)
 {
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = LZ4HC_DEFAULT_CLEVEL;
+	} else if (params->level < 1 || params->level > LZ4HC_MAX_CLEVEL) {
+		/*
+		 * Use < 1 rather than < LZ4HC_MIN_CLEVEL here because
+		 * LZ4HC_compress_generic() only clamps levels below 1
+		 * (levels 1 and 2 are valid). LZ4HC_MIN_CLEVEL (3) is
+		 * advisory and not enforced by the library.
+		 */
+		pr_err("invalid compression level %d\n", params->level);
+		return -EINVAL;
+	}
 
 	return 0;
 }
diff --git a/drivers/block/zram/backend_lzo.c b/drivers/block/zram/backend_lzo.c
index 84330dea6af5..d83f92cf757c 100644
--- a/drivers/block/zram/backend_lzo.c
+++ b/drivers/block/zram/backend_lzo.c
@@ -14,6 +14,14 @@ static void lzo_release_params(struct zcomp_params *params)
 
 static int lzo_setup_params(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
diff --git a/drivers/block/zram/backend_lzorle.c b/drivers/block/zram/backend_lzorle.c
index b3b03a008b64..1b120d062c92 100644
--- a/drivers/block/zram/backend_lzorle.c
+++ b/drivers/block/zram/backend_lzorle.c
@@ -14,6 +14,14 @@ static void lzorle_release_params(struct zcomp_params *params)
 
 static int lzorle_setup_params(struct zcomp_params *params)
 {
+	if (params->dict_sz) {
+		pr_err("dictionary is not supported\n");
+		return -EOPNOTSUPP;
+	}
+	if (params->level != ZCOMP_PARAM_NOT_SET) {
+		pr_err("compression level is not supported\n");
+		return -EOPNOTSUPP;
+	}
 	return 0;
 }
 
diff --git a/drivers/block/zram/backend_zstd.c b/drivers/block/zram/backend_zstd.c
index fb61acdaef67..08da3810cffd 100644
--- a/drivers/block/zram/backend_zstd.c
+++ b/drivers/block/zram/backend_zstd.c
@@ -60,8 +60,13 @@ static int zstd_setup_params(struct zcomp_params *params)
 		return -ENOMEM;
 
 	params->drv_data = zp;
-	if (params->level == ZCOMP_PARAM_NOT_SET)
+	if (params->level == ZCOMP_PARAM_NOT_SET) {
 		params->level = zstd_default_clevel();
+	} else if (params->level < zstd_min_clevel() ||
+		   params->level > zstd_max_clevel()) {
+		pr_err("invalid compression level %d\n", params->level);
+		goto error;
+	}
 
 	zp->cprm = zstd_get_params(params->level, PAGE_SIZE);
 
-- 
2.43.7